by Don Becklin

The CBR1000RR Sheds Pounds and Gains Power

It was going to be tough for me to pass up this opportunity. Not only do I own a 2004 Honda CBR1000RR, but also I rated last year’s bike as my favorite in the street portion of Motorcycle USA’s Superbike Smackdown. Now with subtle but significant tweaks for 2006, it was going to be interesting to see how much better the new bike would be.

Being a press intro novice I had heard all the stories from our editors about the type of pampering that unworthy editorial types receive at these events. My objective would be to avoid having my judgment impaired by the kind of posh treatment that a company like Honda could impose on an easily influenced individual like me. Since Jon Seidel, Honda’s Assistant Press Manager, already knew I was a Honda owner and I have been labeled the resident Honda apologist, there couldn’t have been an easier target in the group of seven assembled journalists. Not so fast, Jonny Boy, my propaganda meter would be on high alert.

Many of you out there might assume that these press events are all play and no work. Ah, but you aren’t aware of the grueling technical briefings that spell out the various changes and upgrades on a new bike release. Imagine sitting at a table for nearly an hour with test rider and former World Endurance Champion Doug Toland along with project leader Noriaki Nakata taking turns giving the intricate details during their presentation. Then there’s the delectable dinner spread that included free drinks and an extremely moist, dense chocolate cake to top it all off. Okay it’s not that tough but you’ve got to work with me a bit here, I’m trying to keep my objectivity and reputation in good stead.

MCUSA’s Editor Kevin Duke gave me a few pointers before I headed out. The first tip was to avoid crashing because you’ll look like a total moron. And second was to try to figure out what the engineers and development staff were trying to achieve during the briefings, then see how well they did once I got to ride the bike. So what did this pseudo-editor learn during these briefings and meet and greet sessions? Well, the biggest thing was that my beloved ’04 CBR was sounding like yesterday’s news.

The 2006 Honda CBR1000RR is a mid-model redesign, taking place two years after the release of the very first CBR Thou in 2004. Do the math and you’ll realize that Honda engineers must have been working on this bike while the ’04 model was being released.

The objectives for the ’06 development team were to lose some weight off the portly CBR, improve its turning capabilities and get a little more power out of the inline-four powerplant. According to Toland, Honda redesigned 60% of all the components on the motorcycle. Honda says 17 pounds have been lopped off and power is up 3%.

Chopping 17 pounds off the bike is probably the biggest achievement of the design team. Parts getting the liposuction treatment include the exhaust system, a new magnesium ACG cover, a smaller ECU black box, thinner brake rotors and even thinner-walled camshafts. The Honda team led by Nakata spared no detail in trying to get the weight down to rival open-class sportbikes. For example, the thickness of the brake rotors went from 5.0mm to 4.5mm, which garnered a 300-gram weight reduction even though the diameter of the rotors increased from 310mm to 320mm. Shaving grams to shed pounds is necessary when a bike is receiving a mid-model makeover.

Getting the weight of the big CBR into the ballpark should reap rewards like improved stopping, handling and acceleration. But simply getting the weight down wasn’t enough for Team Honda. Sharpening the turning capabilities of the CBR would take more than getting the bike into fighting shape, so Honda made subtle mods to its chassis geometry.

Toland stressed that the development team wanted to improve turn-in characteristics and make side-to-side transitions quicker and easier. And here’s where changes were made that you can’t do at home on your pre-2006 model. The steering head angle was reduced by a 0.25 degree while its trail figure was shortened 2mm to 100mm. Then Honda trimmed 4mm off the swingarm, helping shrink the CBR’s wheelbase from 55.6 inches to 55.3 inches. The fork springs are now made from a different material (Kryptonite perhaps?) with a different spring rate and preload. The rear shock spring goes from a 12.0 kg/mm to an 11.5 kg/mm rate combined with a new suspension linkage that provides a more linear rate than previous.

The chassis and suspension changes at first appear slight and made me wonder if I could get close by doing a few garage mods to my ol’ Honda. Reduce the swingarm length by taking a link out of the chain. Get the front forks revalved and replace the stock shock with an Ohlins unit. Change the geometry? That might take a slightly more aggressive approach, something like ramming the front tire into a brick wall at moderate speed. Sure it’s doable, but it sounds like a little more work than my dainty hands are accustomed to, awfully unscientific, and quite possibly dangerous to my skeletal structure.

Boosting power in an open-class sportbike is a little like giving a thoroughbred race-horse the whip. Seems like a great idea until the ride gets cut short thanks to over-exuberance. Since these types of bikes are already pumping out 145+ rear-wheel horsepower, bumping up the engine performance is a game that Honda chooses to balance out with street friendliness. With Honda’s vast racing background, creating a world-beating monster sportbike shouldn’t be much of a problem, but Honda tells us they want to make the bike friendly on the street while still keeping it potent on the track. But when Kawasaki and Suzuki unleash wild performance beasts on the world like the ZX-10R and GSX-R1000, the CBR seems slightly domesticated.

The list of engine changes sound similar to what roadracers typically do to their production race bikes. The majority of work took place in the cylinder head where the intake and exhaust port shapes were changed to improve flow and the combustion chamber volume was reduced to boost the compression ratio from 11.9:1 to 12.2:1. The valve timing was altered and more lift added to the intake side, and the valves themselves were lightened by removing material around where the valves seat. And Honda bumped the redline from 11,650 to 12,200 rpm. To handle the extra stress of the higher compression ratio and additional revs, Honda went to a double valve spring design on the intake valves and strengthened the crankshaft. The additional power also allowed Honda to add a tooth to the rear sprocket to help improve acceleration without affecting top-speed.

Doing the math on the 145.5 rear-wheel horsepower our 2005 Honda CBR1000RR test bike we had on the dyno last year, Honda’s claim of a 3% power increase would net a 4.4 hp increase to a final number of 149.9 hp, right in the 150-151 hp range of the ZX and GSX-R.

So I could give my 2004 CBR motor the ol’ racer’s massage by yanking it out of the chassis and sending it to the local race motor guy. Changing the gearing is a snap and bingo, I’ve got mo’ mo’ power. Of course getting the motor out of the bike is a project I don’t really have time for, the race prep job would probably cost me $3K in parts, and my Honda factory warranty gets thrown out the window. Hmm.

Hopping on the revised CBR while it’s on a stand doesn’t exactly make you go wow; in fact I was looking the bike over in the hotel conference room trying to find something different than my CBR. The new bike feels ergonomically identical to the previous model and the Honda guys admitted that the only difference in ergonomics is the new softer seat foam. Hey, at least they didn’t make the seat foam harder! So the changes touted by the presenters would have to be evaluated once I was permitted to ride the bike.

Bridgestone was in attendance touting their new BT-015 Radial street tire that comes standard on 50% of the new CBRs. We would ride the morning sessions on the BT-015 and then get the sticky DOT Race BT-002 tires for the afternoon. Honda and Bridgestone had actually spent one full day scrubbing in all the tires, and each bike would be fitted with tire warmers too. Sounds a little excessive but then again, anything to help out a ham-fist like myself from crashing on the first lap is appreciated.